NEW YORK (Reuters) - The CEOs of the three largest U.S. airlines have asked to meet with Secretary of State Rex Tillerson to discuss allegations that Gulf states are unfairly subsidizing state-owned carriers, driving down prices and crowding out competition on key routes, accusations those carriers deny.

The chief executives of American Airlines Group Inc <AAL.O>, United Continental Holdings Inc <UAL.N> and Delta Air Lines Inc <DAL.N> asked for the meeting in a letter posted on the website of the U.S. airlines-backed Partnership for Open & Fair Skies.

"We are writing to bring to your attention an issue of utmost importance to the future of our industry: the massive subsidization of three state-owned Gulf carriers – Qatar Airways, Etihad Airways and Emirates – and the significant harm this subsidized competition is causing to U.S. airlines and U.S. jobs," the letter, sent on Wednesday, said.

"The Gulf carriers have received over $50 billion in documented subsidies from their government owners since 2004," the airlines contend to Tillerson, who was sworn in as secretary of state that same day.

Duties of the U.S. secretary of state, the nation's top diplomat, include facilitating economic discourse between the United States and other countries.

Officials under former President Barack Obama convened talks on the topic but did not make the progress U.S. airlines expected.

Under changes promised by President Donald Trump, who campaigned heavily on fighting against countries taking advantage of trade deals with the United States, the largest U.S. carriers are hoping for a crackdown on foreign interference in American markets.

Chief Executive James Hogan of Etihad Aviation Group, which flies to six cities in the United States, on Wednesday said the Gulf carriers will have to wait and see if Trump reopens the Open Skies debate.

"We are not flying into any further points in the U.S.," Hogan told reporters in Abu Dhabi on Wednesday. "We are very comfortable with our American network."

"In regards to how that's addressed moving forward, we have to wait and see," he said.

Open Skies agreements reduce restrictions on flying to and from partner states.

Not all U.S. airlines are opposed to maintaining agreements with these nations.

The air cargo unit of FedEx Corp (FDX.N), JetBlue Airways Corp (JBLU.O), Atlas Air Worldwide Holdings Inc (AAWW.O) and Hawaiian Holdings Inc (HA.O) banded together to create U.S. Airlines for Open Skies Coalition, which backs the Gulf-carriers' cause.

(Reporting by Alana Wise in New York; Additional reporting by Jeffrey Dastin in San Francisco, Stanley Carvalho in Abu Dhabi and Victoria Bryan in Berlin; editing by Bernard Orr and Dan Grebler)